Remove Puma::Delegation (#2000)

Replace with Forwardable.

lib/puma/client.rb

@@ -9,8 +9,8 @@ class IO
 end
 
 require 'puma/detect'
-require 'puma/delegation'
 require 'tempfile'
+require 'forwardable'
 
 if Puma::IS_JRUBY
   # We have to work around some OpenSSL buffer/io-readiness bugs
@@ -41,7 +41,7 @@ module Puma
     EmptyBody = NullIO.new
 
     include Puma::Const
-    extend  Puma::Delegation
+    extend Forwardable
 
     def initialize(io, env=nil)
       @io = io
@@ -83,7 +83,7 @@ module Puma
 
     attr_accessor :remote_addr_header
 
-    forward :closed?, :@io
+    def_delegators :@io, :closed?
 
     def inspect
       "#<Puma::Client:0x#{object_id.to_s(16)} @ready=#{@ready.inspect}>"

lib/puma/delegation.rb

@@ -1,13 +0,0 @@
-# frozen_string_literal: true
-
-module Puma
-  module Delegation
-    def forward(what, who)
-      module_eval <<-CODE
-        def #{what}(*args, &block)
-          #{who}.#{what}(*args, &block)
-        end
-      CODE
-    end
-  end
-end

lib/puma/server.rb

@@ -9,13 +9,13 @@ require 'puma/null_io'
 require 'puma/reactor'
 require 'puma/client'
 require 'puma/binder'
-require 'puma/delegation'
 require 'puma/accept_nonblock'
 require 'puma/util'
 
 require 'puma/puma_http11'
 
 require 'socket'
+require 'forwardable'
 
 module Puma
 
@@ -32,7 +32,7 @@ module Puma
   class Server
 
     include Puma::Const
-    extend  Puma::Delegation
+    extend Forwardable
 
     attr_reader :thread
     attr_reader :events
@@ -89,10 +89,7 @@ module Puma
 
     attr_accessor :binder, :leak_stack_on_error, :early_hints
 
-    forward :add_tcp_listener,  :@binder
-    forward :add_ssl_listener,  :@binder
-    forward :add_unix_listener, :@binder
-    forward :connected_port,    :@binder
+    def_delegators :@binder, :add_tcp_listener, :add_ssl_listener, :add_unix_listener, :connected_port
 
     def inherit_binder(bind)
       @binder = bind